Ribbon feed cartridge

ABSTRACT

A ribbon feed cartridge for use with a chain printer consists of a rectangular plate carrying on one side spaced spools for storage of an inking ribbon while supporting, at the four corners on the opposite side of the plate, guide rolls defining a rectangular ribbon loop with the ribbon crossing over from side to side above one longitudinal edge of the plate. Pin and slot locking means allow the plate to be locked in place in parallel with the chain printer with a longitudinal run of the inking ribbon lying beneath the moving chain type carrier. Coupling of the ribbon feed cartridge plate to the chain printer support plate forces one end of the ribbon loop into contact with a capstan for driving the same.

United States Patent 1 91 Dowd 45] Apr. 24, 1973 1 RHBBGN FEED CARTRHDGE [75] inventor: Albert A. Dowd, Vestal, NY.

[73] Assignee: International Business Machines Corporation, Armonk, N.Y.

22 Filed: Aug.7, 1970 21 Appl No.: 62,119

[52] US. Cl. ..l01/336,197/151,197/168 [51] Int. Cl. ..B41l 27/18 [58] Field of Search ..197/151, 168;

101/336; 179/100.2 Z; 274/4 B,4C,4 D, 11 F, 11 B, 1 l C, 11 D; 242/5519 R, 5519A [56] References Cited UNITED STATES PATENTS 1/1970 Hladky ..242/55.19 R X 6/1971 Malkowski ..242/55. 19 A X l 5 7 ABSTRACT A ribbon feed cartridge for use with a chain printer consists of a rectangular plate carrying on one side spaced spools for storage of an inking ribbon while supporting, at the four corners on the opposite side of the plate, guide rolls defining a rectangular ribbon loop with the ribbon crossing over from side to side above one longitudinal edge of the plate. Pin and slot locking means allow the plate to be locked in place in parallel with the chain printer with a longitudinal run of the inking ribbon lying beneath the moving chain type carrier. Coupling of the ribbon feed cartridge plate to the chain printer support plate forces one end of the ribbon loop into contact with a capstan for driving the same.

8 (Ilaims, 4 Drawing Figures "PATENTED APR 24 I975 SHEET 1 OF 2 INVE/VTQR ALBERT A. DOWD ATTORNEYS PATENTEDAPR 24 1915 SHEET 2 BF 2 FIG. 3

RIBBON FEED CARTRIDGE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a ribbon feed cartridge for supporting a large ribbon loop in proximity to an endless type chain for a chain printer or the like, and more particularly, to a cartridge which is readily coupled to the chain printer and which automatically places the inking ribbon in proper position with respect to the printer type members and frictionally engages the ribbon loop to powered ribbon driving means.

2. Description of the Prior Art Regardless of the type of printer, one'of the aspects of printer operation which is universally disliked is the messiness and complexity of inking ribbon changing. This results in many service calls which are due primarily to improper ribbon installation, to the great annoyance of both the operator of the printer and the service personnel. Further, improper ribbon installation often results in damage to the printer and great delay in operation of the same due to the time involved in cleaning up the resulting mess, and proper replacement of a new ribbon. Further, as printer speeds increase, ribbon changing becomes more frequent.

Attempts have been made to provide cartridges carrying one or more spools for storing the inking ribbon, but in each case a portion of the ribbon must be partially removed from the cartridge and properly threaded through guides of the printer prior to operating the same. Contact of the operator with the inked ribbon normally involves transfer of some ink to the operators hands with some consternation to the operator.

SUMMARY OF THE INVENTION The object of the present invention is to ensure that ribbon changing is clean, convenient and foolproof by the employment of a cartridge in which the ribbon is in proper position such that after cartridge insertion within the printer, printing may occur immediately without any adjustments or shifting of ribbon portions relative to the type carrier or the like. The present invention, by containing the ribbon in a cartridge, eliminates the need for ribbon threading and makes it possible to install an inking ribbon by simply plugging it in the printer. While the arrangement illustrated and described with respect to the present invention is particularly adaptable to chain printers, it is readily adaptable to other printer types wherein the inking ribbon used constitutes a narrow, endless ribbon. Alternatively, the ribbon may be fed from a supply spool to a pick-up spool on the same side of the cartridge support plate but looped on the opposite side about multiple guide rolls at the four plate corners.

In one form, the ribbon feed cartridge of the present invention is adapted for use with an endless chain printer having an endless chain type carrier extending between spaced sprocket wheels for moving the individual type into imprint position. The cartridge comprises essentially an elongated support plate with spaced inking ribbon storage spools mounted on the side of the plate opposite that facing the chain type carrier. The ribbon may be an endless ink carrying web. Guide rolls are each mounted for rotation about an axis parallel to that of the spools on the other side of the cartridge support plate to define a large rectangular ribbon loop with portions of the ribbon crossing over from one side to the other above one longitudinal edge of the cartridge plate. This provides a large longitudinal run of ribbon in juxtaposition to a similar longitudinal run of the type chain.

In essence the concept of the present invention comprises a ribbon cartridge having a storage area on one side of a support plate and a single loop of ribbon on the other side, essentially surrounding an endless type chain. This allows single ribbon replacement by first moving the ribbon normal to the chain.

Preferably, fixed mounting pins are carried by the plate surrounding the chain type carrier, which pins extend outwardly toward the cartridge. The cartridge plate is slotted to receive the pins, whereby insertion of the pins in the slots and movement of the same to a locked position, positions the longitudinal run of the inked ribbon in proper position for printer operation. Preferably, a fixed cartridge locator block supports a power drive capstan in position to contact the inserted end of the ribbon loop with the ribbon pressing against the same. A shiftable pressure roll is carried within a slot of the cartridge plate, internally of the loop and at the inserted end of the cartridge plate and is movable at right angles to the direction of cartridge insertion. The pressure roll lies intermediate of the guide rolls at the inboard corners of the cartridge and insertion of the cartridge into abutting contact with the cartridge locator block causes the portion of the ribbon intermediate of the pressure roll and one of the guide rolls to wrap about the periphery of the capstan while the shiftable pressure roll sandwiches the tape against the capstan. Spring biased pressure arms carried by the cartridge locator block press against the pressure roll to force the endless ribbon in contact with the capstan to allow the capstan to frictionally drive the tape between the spools. A microswitch senses contact of the inserted end of the cartridge and the self-applied tension on the ribbon. Increase of tension due to ribbon jam drives the cartridge away from the cartridge locator block, disengaging the capstan from the ribbon and terminating drive of the same.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an exploded, perspective view of the principal components of a chain printed employing the improved inking ribbon feed cartridge of the present invention.

FIG. 2 is a perspective view of the chain printer of FIG. 1 including the ribbon feed cartridge cover in assembled position, from the reverse side thereof.

FIG. 3 is a side elevational view of a portion of the chain printer of FIG. 1 prior to insertion of the cartridge into the printer and in contact with the cartridge locator block.

FIG. 4 is a side view, similar to that of FIG. 2, with the cartridge fully inserted.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, the inking ribbon feed cartridge of the present invention is illustrated generally at 10, in FIG. i, for use in conjunction with a chain printer 11 including as its principal components a chain type carrier 12, and in FIG. 3, a fixed cartridge locator block 14 including a power driven cylindrical capstan 16 which is mounted for rotation in a clockwise direction, on a support shaft 18. The chain printer 11 further includes a pair of longitudinally spaced sprocket wheels 20 and 22 supporting the endless chain type carrier 12, comprising linked type segments 24 carrying type font characters (not shown) on their outer faces. In operation, one or more hammers, 30, FIGS. 3 and 4, is selectively moved into contact with the print media 32 and one type carrier segment 24 with inking ribbon 34 interspersed therebetween to imprint the print media 32 in conventional fashion. A type chain support plate 36, which carries the spaced sprocket wheels 20 and 22 supports, at spaced longitudinal positions, fixed mounted'pins 38 having enlarged heads 40 to be used as hereinafter described for positively supporting and locating the ribbon cartridge 10 with respect to the endless chain printer 1]..

In this respect, the printing ribbon cartridge 10 consists primarily of a configured, elongated metal cartridge support plate 42 which has coupled to its outboard end, a grip or carrying handle 44 defined by slot 46, for inserting the cartridge 10 into the chain printer 1] such that the inboard end 48 abuts the face 50 of the fixed cartridge locator block 14. The plate 42 is of modified H-shape configuration, having projections 52 and 54 extending upwardly from the upper longitudinal edge 56 and projections 58 and 68 extending downwardly from the lower longitudinal edge 62, the projections 52, 54, 58 and 60 being located at the four corners of the plate 42. A pair of spools 66 and 68 are rotatably mounted on the right hand side or face 64 of the plate 42. The ribbon 34 comprises an endless inking ribbon, stored in the form of large loops on the spaced spools 66 and 68, with few convolutions and is movable therebetween. The number of convolutions is a critical ingredient of endless ribbon performance. The spools 66and 68 are each mounted for rotation about'their axis by shafts 70 which project outwardly from the face 64 of plate 42. Fixed ribbon guides 71 may be provided between spools 66 and 68. Thus, the plate 42 serves as the backbone for the ribbon cartridge 10, carrying all of the ribbon storage spools as at 66 and 68 on one side. This further facilitates ease and cleanliness in ribbon changing since the spools 66 and 68 are surrounded by cover 65, FIG. 2. Cover 65 functions to maintain the ribbon 34 free from contamination, since only a single loop extends outside of the cover 65 during usage. Further the cover 65 provides a second hand hold during installation and provides some structural rigidity to the ribbon cartridge 10. Cover 65 is coupled by means (not shown) to side 64 of support plate 42.

On the opposite side, the same support plate 42 carries all of the guide and the ribbon feed pressure rolls. In this regard, four ribbon guide rolls, 72, 74, 76 and 78, are mounted for rotation about their axes on the side of projections 52, 54, 58 and 60, respectively, being supported by suitable mounting pins 79 which extend outwardly on the face 69 of plate 42 opposite from face 64 which carries the ribbon storage spools 66 and 68 and generally at right angles thereto. The periphery of the guide rolls 72 and 74 lies above edge 56 of plate 42 to allow the ribbon 34 to cross from one side of plate 42 to the other without interference. In thisregard, the

heights of the guide rolls 72 and 74 may be slightly different to prevent contact between the portions A and B of ribbon 34 which cross and overlie the upper longitudinal edge 56'of plate 42. Thus, a large supply of ribbon 34 is stored as long loops between the ribbon spools 66 and 68 while only one turn of the same crosses at A and B to the opposite side of plate 42 and returns therefrom, defining on that side a rectangular loop having an outboard vertical portion C, a longitudinally extending loop portion D in imprint position and, in this case, a short inboard vertical portion E extending between the fixed axis guide rollers 74 and 78.

Plate 42 is provided with an elongated vertical slot 80 which carries a pin or shaft 82 of a diameter slightly less than the width of the slot 80, the pin 82 rotatably supporting a pressure roll 84. In turn, at the opposite end of the pressure roll 84 the shaft 82 projects therefrom and is received within an elongated slot 86 formed within a small generally rectangular plate 88. The plate 88 is fixedly coupled to the cartridge support plate 42 but spaced therefrom on the left hand face 69 thereof by paired screws 90. Thus, the pressure roller 84 may rise or fall within vertical slots 80 and 86, when its periphery is in contact with portion E of the inkin ribbon 34.

Turning to the fixed cartridge locator block 14 which defines the extent of insertion of the ribbon cartridge 10, it is noted that the locator block 14 carries a pair of laterally displaced pressure arms 92' having recessed surface portions 94 just behind tapered or inclined contact edge 95, which contact shaft 82 carrying the pressure roll 84 to ride on the same. Further, the pressure arms 92 are coupled together by an intermediate block 96 and are supported for rotation about the axis of mounting pin 98, the pin 98 extending laterally from the side of locator block 14. Further, the locator block 14 carries a tension spring 100, one end of which is coupled to the locator block 14 by pin 102, while the other end is coupled to car 104 which extends outwardly from intermediate block 96. Further, the fixed cartridge locator block 14 carries a laterally extending stop in the form of a pin 106 which lies intermediate of the spring 108 and the pressure arm pivot shaft 98. Thus, normally, the tension of spring biases the right hand end of the pressure arms 92, FIG. 3, upwardly against the stop 106.

What occurs during insertion of the cartridge 10 may be readily seen by reference to FIGS. 3 and 4. When the cartridge support plate 42 is coupled to heated mounting pins 38 on support plate 36 of printer 11, the heads 48 pass through a cooperating enlarged circular portion 41 of each locking slot 39 in support plate 42, and with the heads 40 projecting through the enlarged circular slot portion 41, the cartridge 10 is shifted from left to right as indicated by arrow 45 with each pin 38 moving to the full left end of its slot 39. This moves the cartridge 10 from the position shown in FIG. 1 to the position shown in FIG. 2. In this case, the inboard end 48 of the cartridge 10 abuts or nearly abuts the end face 50 of the fixed cartridge locator block 14. At the same time, the portion E of the inking ribbon 34 makes initial contact with the periphery of capstan 16, with the capstan l6 riding up and over the lower right hand corner guide roll 78. The portion E of the inking ribbon 34 contacts capstan l6 and curves about the periphery of the guide roll 78, as the capstan 16 moves up and over this guide roll 78 to the position shown in FIG. 4. At the same time, the capstan 16 in contacting the outside surface of ribbon portion E causes the pressure roll 84 to shift upwards with pin 82 sliding within vertical slots 80 and 86 of cartridge support plate 42 and plate 88, respectively. Simultaneously, the tapered surface portion 95 of each pressure arm 92 contacts the pin 82 supporting the pressure roll 84 with the pin 82 moving into arcuate recess 94 just as the inboard end 48 of the cartridge contacts the end face 50 of the fixed cartridge locator block 14. In moving roll 84 upwardly, necessarily, the arms 92 are rotated clockwise about the axis of mounting pin 98, stretching the tension spring 100 and providing a biasing effect tending to maintain ribbon portion E in good frictional contact with the periphery of capstan l6 and clamping the ribbon 34 between the capstan 16 and rolls 84 and 78. With power applied to the capstan 16, it rotates clockwise, FIG. 4, and the ribbon 34 moves from left to right as indicated by arrow 89, beneath the chain type carrier 12.

Of course, should the tension of ribbon 34 increase due to jamming of the ribbon 34, the ribbon portion E automatically exerts a force, pushing the cartridge 10 outwardly, that is, away from the fixed cartridge locator block 14 to cause the ribbon portion E to again lie flat between guide rolls 74 and 78 with the pressure arms 92 released from the pressure roll support pin 82.

However, any tendency for self-shifting of the cartridge 10 results in a change of state of a microswitch 110, which is mounted in a cavity 112 within the end face 50 of the fixed cartridge locator block 14. The movable plunger 114 of the microswitch 110 moves outwardly, opening the switch contacts (not shown) to change the electrical signal emanating from microswitch leads 116 and to readily indicate disengagement of the ribbon 34 from its driving means, capstan 16.

From the above description, it is seen that the ribbon cartridge 10 assures foolproof, convenient and clean ribbon installation on a printer. There is no need for the operator to handle the ribbon 34 proper. All the operator has to do is grasp the handle 44 to either insert the cartridge 10 in proper position or remove the same. A dual action occurs when ribbon jams or other actions sufficiently increase the tension of the ribbon 34 at the capstan 16. Straightening of ribbon 34 causes the cartridge 10 to move away from the fixed cartridge locator block 14. However, with the plunger 114 of the microswitch 110 readily sensing movement of the cartridge 10 toward eject position, that is, from right to left, the signal emanating from leads 116 may be readily applied to cut off energy to the capstan drive motor (not shown), thus, preventing continuing feeding of th ribbon 34.

The large span between ribbon spools 66 and 68 permits large yardage of ribbon 34 with a minimum of convolutions, hence, long life of the same without excess tension. This large span also results in minimum distortion in moving from the storage area to the usage areas.

Further, while the invention has been applied to a cartridge specifically employed in carrying a continuous loop of linked ribbon for movement into underlying position with respect to the individual type segments of a chain printer, it is obvious that the invention has application to cartridges in general for feeding of photographic and magnetic film. Further, the use of a continuous inking ribbon prevents the inadvertent disconnecting of either the leading or trailing end of the ribbon tothe feed or to the supply and take-up reels, where, in a somewhat more conventional system, the functions of take-up and supply reels may be, in fact, reversed at various times.

What is claimed is:

1. A ribbon feed cartridge for use with a chain printer or the like, including a longitudinally extending array of adjoining type carriers, an imprint medium adjacent to said type carriers, and selectively operable hammer means in juxtaposition to said imprint medium and said type carriers for effecting imprinting, said cartridge comprising:

an elongated cartridge support plate,

spaced inked ribbon storage spools mounted on one side of said plate and supporting an inked ribbon therebetween,

a plurality of guide rolls, each mounted on the other side of said plate from said spools and supporting a portion of said ribbon in the form of a loop surrounding said array of type carriers with portions crossing and recrossing from one side of said plate to the other, said loop including a large longitudinal run which lies beneath said crossed ribbon portions and extends parallel with said type carriers and between said imprint medium and said adjoining type carriers.

2. The ribbon feed cartridge as claimed in claim 1 for use in a chain printer further comprising: a type carrier support plate, and wherein adjoining type carriers define an endless loop carried by said type carrier support plate and said printer further comprises: means for moving said ribbon relative to said type carriers, and means for coupling said elongated cartridge support plate to said carrier support plate with said longitudinal run of said inked ribbon lying in juxtaposition to said array of type carriers.

3. The ribbon feed cartridge as claimed in claimed in claim 2, wherein said type carrier loop is driven by longitudinally spaced sprockets rotatably mounted on said carrier support plate and positioned on one face thereof, and said means for coupling said plates together comprises mounting pins extending laterally from said one face of said carrier support plate and corresponding mounting and locking slots carried by said cartridge support plate for receiving said mounting pins.

4. The ribbon feed cartridge, as claimed in claim 3 wherein said means of said printer for moving said ribbon relative to said type carriers comprises a power driven capstan positioned to drivingly engage said ribbon loop on the side of said cartridge support plate carrying said plurality of guide rolls, and said cartridge support plate further includes elongated slot means, and a pressure roll mounted on said cartridge support plate on the side carrying said guide rolls in contact with said ribbon for pressing said ribbon about the periphery of said capstan to ensure driving movement of said ribbon during rotation of said capstan,

said pressure roll having support pins slidable within said elongated slot means whereby said pressure roll is shiftable on said cartridge support plate by driving contact of said ribbon by said capstan.

5. The ribbon feed cartridge as claimed in claim 4, wherein said cartridge support plate has four corners and an inboard end, said guide rolls being carried by said cartridge support plate at said four corners including corners proximate said inboard end thereof to define a generally rectangular ribbon loop including a portion extending between said guide rolls on said corners proximate said inboard end of said cartridge support plate, and said capstan makes contact with said portion of said ribbon loop extending between said guide rolls on said inboard end of said cartridge support plate, and said elongated slot means for said support pins of said pressure roll for carrying said pressure roll lies inside said ribbon loop parallel to said portion of said ribbon loop extending between said guide rolls on said inboard end of said cartridge support plate, said elongated slot means being located for spacing said pressure roll from one of said guide rolls at one of said corners proximate said inboard end of said cartridge support plate a distance which causes said pressure roll to be shifted by said capstan upon insertion of said cartridge into said printer whereby said ribbon is caused to be frictionally wrapped about said power driven capstan.

6. A ribbon feed cartridge drive system comprising:

a fixed cartridge locator block;

a ribbon feed cartridge comprising an elongated,

generally rectangular cartridge support plate carrying longitudinally spaced spools positioned on one side of said plate for rotation about their axis normal to said plate and supporting a ribbon therebetween,

said cartridge support plate having an inboardend iocatable in substantial abutment with said locator block,

a plurality of fixed guide rolls, each mounted for rotation about its axis and carried on the opposite side of said cartridge support plate, with the axes of rotation of said guide rolls and said spools being generally parallel, v

said fixed guide rolls including certain guide rolls in the vicinity of said inboard end of said cartridge support plate,

said ribbon crossing and recrossing from said one side of said cartridge support plate to said opposite side and contacting the periphery of said guide rolls to define a single ribbon loop on said opposite side of said cartridge support plate,

said ribbon loop including a portion on said guide rolls in the vicinity of said inboard end of said cartridge support plate, I said cartridge support plate further having elongated slot means;

mounting means for mounting said cartridge support plate at a fixed position with respect to said fixed cartridge locator block with said inboard end of said cartridge support plate in substantial abutment with said locator block;

a power-driven capstan mounted for rotation about a fixed axis in front of said cartridge locator block for contacting said ribbon exteriorly along said portion of said ribbon loop in the vicinity of said inboard end of said cartridcge support plate; and a pressure roll carried by sar cartridge support plate in contact interiorly with said ribbon loop,

said pressure roll having support pins slidable in said elongated slot means of said cartridge support plate whereby said pressure roll is shiftable by said capstan upon movement of said cartridge support plate into substantial abutment with said locator block,

and means mounted on said locator block for biasing said pressure roll in opposition to shifting by said capstan whereby during abutting contact of said inboard end of said cartridge support plate and said fixed cartridge locator block, said pressure roll causes a high frictional wrap of said portion of said ribbon in the vicinity of said inboard end of said cartridge support plate about the periphery of said capstan.

7. The ribbon feed cartridge drive system as claimed in claim 6, wherein said biasing means includes at least one pressure arm pivotally mounted on said locator block and extending outwardly therefrom to releasably engage at least one of said support pins of said pressure roll, and a spring normally biasing said pivotabie pressure arm toward said capstan, whereby, in response to movement of said ribbon into contact with the periphery of said capstan upon movement of said cartridge into abutment with said locator block, said capstan causes said pressure roll to pivot said pressure arm against the bias of said spring to thereby maintain frictional contact between the periphery of said capstan and said ribbon wrapped thereabout.

8. The ribbon feed cartridge drive system as claimed in claim 7, wherein said fixed cartridge locator block includes a recess within the face thereof facing said inboard end of said cartridge support plate, and means for sensing the motion of said cartridge support plate into and out of abutting contact with said cartridge locator, block comprising a microswitch positioned within said recess and having a plunger element extendable beyond said face of said block for depression thereof to actuate said microswitch upon contact with said inboard end of said cartridge support plate. 

1. A ribbon feed cartridge for use with a chain printer or the like, including a longitudinally extending array of adjoining type carriers, an imprint medium adjacent to said type carriers, and selectively operable hammer means in juxtaposition to said imprint medium and said type carriers for effecting imprinting, said cartridge comprising: an elongated cartridge support plate, spaced inked ribbon storage spools mounted on one side of said plate and supporting an inked ribbon therebetween, a plurality of guide rolls, each mounted on the other side of said plate from said spools and supporting a portion of said ribbon in the form of a loop surrounding said array of type carriers with portions crossing and recrossing from one side of said plate to the other, said loop including a large longitudinal run which lies beneath said crossed ribbon portions and extends parallel with said type carriers and between said imprint medium and said adjoining type carriers.
 2. The ribbon feed cartridge as claimed in claim 1 for use in a chain printer further comprising: a type carrier support plate, and wherein adjoining type carriers define an endless loop carried by said type carrier support plate and said printer further comprises: means for moving said ribbon relative to said type carriers, and means for coupling said elongated cartridge support plate to said carrier support plate with said longitudinal run of said inked ribbon lying in juxtaposition to said array of type carriers.
 3. The ribbon feed cartridge as claimed in claimed in claim 2, wherein said type carrier loop is driven by longitudinally spaced sprockets rotatably mounted on said carrier support plate and positioned on one face thereof, and said means for coupling said plates together comprises mounting pins extending laterally from said one face of said carrier support plate and corresponding mounting and locking slots carried by said cartridge support plate for receiving said mounting pins.
 4. The ribbon feed cartridge, as claimed in claim 3 wherein said means of said printer for moving said ribbon relative to said type carriers comprises a power driven capstan positioned to drivingly engage said ribbon loop on the side of said cartridge support plate carrying said plurality of guide rolls, and said cartridge support plate further includes elongated slot means, and a pressure roll mounted on said cartridge support plate on the side carrying said guide rolls in contact with said ribbon for pressing said ribbon about the periphery of said capstan to ensure driving movement of said ribbon during rotation of said capstan, said pressure roll having support pins slidable within said elongated slot means whereby said pressure roll is shiftable on said cartridge support plate by driving contact of said ribbon by said capstan.
 5. The ribbon feed cartridge as claimed in claim 4, wherein said cartridge support plate has four corners and an inboard end, said guide rolls being carried by said cartridge support plate at said four corners including corners proximate said inboard end thereof to define a generally rectangular ribbon loop including a portion extending between said guide rolls on said corners proximate said inboard end of said cartridge support plate, and said capstan makes contact with said portion of said ribbon loop extending between said guide rolls on said inboard end of said cartridge support plate, and said elongated slot means for said support pins of said pressure roll for carrying said pressure roll lies inside said ribbon loop parallel to said portion of said ribbon loop extending between said guide rolls on said inboard end of said cartridge support plate, said elongated slot means being located for spacing said pressure roll from one of said guide rolls at one of said corners proximate said inboard end of said cartridge support plate a distance which causes said pressure roll to be shifted by said capstan upon insertion of said cartridge into said printer whereby said ribbon is caused to be frictionally wrapped about said power driven capstan.
 6. A ribbon feed cartridge drive system comprising: a fixed cartridge locator block; a ribbon feed cartridge comprising an elongated, generally rectangular cartridge support plate carrying longitudinally spaced spools positioned on one side of said plate for rotation about their axis normal to said plate and supporting a ribbon therebetween, said cartridge support plate having an inboard end locatable in substantial abutment with said locator block, a plurality of fixed guide rolls, each mounted for rotation about its axis and carried on the opposite side of said cartridge support plate, with the axes of rotation of said guide rolls and said spools being generally parallel, said fixed guide rolls including certain guide rolls in the vicinity of said inboard end of said cartridge support plate, said ribbon crossing and recrossing from said one side of said cartridge support plate to said opposite side and contacting the periphery of said guide rolls to define a single ribbon loop on said opposite side of said cartridge support plate, said ribbon loop including a portion on said guide rolls in the vicinity of said inboard end of said cartridge support plate, said cartridge support plate further having elongated slot means; mounting means for mounting said cartridge support plate at a fixed position with respect to said fixed cartridge locator block with said inboard end of said cartridge support plate in substantial abutment with said locator block; a power-driven capstan mounted for rotation about a fixed axis in front of said cartridge locator block for contacting said ribbon exteriorly along said portion of said ribbon loop in the vicinity of said inboard end of said cartridge support plate; and a pressure roll carried by said cartridge support plate in contact interiorly with said ribbon loop, said pressure roll having support pins slidable in said elongated slot means of said cartridge support plate whereby said pressure roll is shiftable by said capstan upon movement of said cartridge support plate into substantial abutment with said locator block, and means mounted on said locator block for biasing said pressure roll in opposition to shifting by said capstan whereby during abutting contact of said inboard end of said cartridge support plate and said fixed cartridge locator block, said pressure roll causes a high frictional wrap of said portion of said ribbon in the vicinity of said inboard end of said cartridge support plate about the periphery of said capstan.
 7. The ribbon feed cartridge drive system as claimed in claim 6, wherein said biasing means includes at least one pressure arm pivotally mounted on said locator block and extending outwardly therefrom to releasably engage at least one of said support pins of said pressure roll, and a spring normally biasing said pivotable pressure arm toward said capstan, whereby, in response to movement of said ribbon into contact with the periphery of said capstan upon movement of said cartridge into abutment with said locator block, said capstan causes said pressure roll to pivot said pressure arm against the bias of said spring to thereby maintain frictional contact between the periphery of said capstan and said ribbon wrapped thereabout.
 8. The ribbon feed cartridge drive system as claimed in claim 7, wherein said fixed cartridge locator block includes a recess within the face thereof facing said inboard end of said cartridge support plate, and means for sensing the motion of said cartridge support plate into and out of abutting contact with said cartridge locator block comprising a microswitch positioned within said recess and having a plunger element extendable beyond said face of said block for depression thereof to actuate said microswitch upon contact with said inboard end of said cartridge support plate. 